On a recent Thursday, on a night so cold that delivery is the only sensible option, Margaux, a 3-week-old restaurant within the recently restored Marlton Hotel, is overflowing with beautiful people seemingly immune to frostbite.

There’s Lauren Bush Lauren with hubby — and Ralph Lauren’s son — David Lauren drinking wine at one table. Party fotog Billy Farrell at another. In the adjacent atrium sits a coterie of art powerhouses including British painter Cecily Brown and sculpturist/Marc Jacobs muse Rachel Feinstein; beside them, newly minted tech millionaires such as Bleacher Report co-founder Bryan Goldberg (who sold the site for a tidy $200 million in 2012) hobnob over sunchoke chips.

The spot has become a hangout for the likes of Lauren Bush Lauren, her husband, David Lauren (far left), and brother-in-law, Andrew Lauren.Photo: Brian Zak

It’s a different crowd than the one that used to flock to the Marlton decades ago, when the Eighth Street hotel was a favorite haunt of beatnik writer Jack Kerouac.

“Kerouac would be disgusted and spit on this place and go down the street and order a beer,” admits the eatery’s owner, Sean MacPherson, a 49-year-old surfer-cum-restaurateur who has fathered a number of NYC hot spots — including the Bowery Hotel, the Waverly Inn and the Jane Hotel. Margaux is poised to become his next big hit.

“This is the new Beatrice Inn,” declares Kim McCall, a 34-year-old charity exec, who checked out the scene two weeks ago.

And what a scene it is. Margaux isn’t even a month old and it’s already had fetes for the likes of designer Olivier Theyskens, and is set to host a slew of upcoming Fashion Week bashes, including one for designer Prabal Gurung.

While the haunt exudes a clubhouse sparkle, MacPherson, who has the demeanor of a sun-dazed professor, doesn’t want the place to shine too brightly.

“I try to build things that people may not talk about, but they’re places that people naturally gravitate towards,” says MacPherson, praising the “run-down, slightly grandmother-ish” Algonquin lobby bar as his perennial inspiration.

“Perfect places ultimately are not really of interest to me.

“Take the Four Seasons Restaurant,” he continues. “It’s a little oppressive. It’s an intensely beautiful place and I really appreciate it and I’m happy it’s landmarked and I’m happy it’s there — and I’m happy I don’t have to eat there every day.”

He insists that after the initial hype dies down, Margaux, which is heavy on vegetarian options, is “very much designed to be a neighborhood spot.” The taste-maker even plans to make his own high chairs to meet his aesthetic standards.

“The ones out there are really ugly,” says MacPherson, who recently had his second child, a son named Dashiell, with wife Rachelle Hruska, the fetching 30-year-old founder of party site Guest of a Guest.

The vegetarian-friendly menu offers a “Farmer’s Board” of pureed veggies and grains.

The chic clan splits its time between the West Village and Montauk, and MacPherson is adamant that having children doesn’t mean he’s losing his cool.

“I would not get rid of my motorcycle because I have kids,” he says. “I’d just buy them little minibikes.”

While Margaux continues to bask in the limelight, MacPherson is already at work on his next project, a restaurant at the long-delayed Hotel Ludlow on the Lower East Side.

He’s partnered with the Torrisi team — the young lads behind cult spots Torrisi, Parm, Carbone and ZZ’s Clam Bar — despite dissing them in a recent newspaper article, calling Carbone “fake” and saying he was “embarrassed to be there.”